Numerical study of the fluid-dynamic loading on pipes conveying fluid with a laminar velocity profile

Abstract

The paper deals with the fluid-dynamic forces of laminar fluid flow in long vibrating pipes as well as in long curved pipes at rest. It focuses on the contribution of the fluid-dynamic force related to the centrifugal acceleration. The study is based on the results of a CFD numerical model of an incompressible laminar fluid flow in the pipe, which is deflected in a bending, beam-type mode. The results are presented in terms of the centrifugal correction factor, which is defined as the ratio between the actual centrifugal-related term of the observed fluid-dynamic force and the solution of the one-dimensional model. The estimated values of the respective correction factor are presented for a range of vibration frequencies, lengths of the pipe and amplitudes of the pipe deflection. The results show that all the listed parameters affect the centrifugal correction factor. The resulting values are also compared and assessed with respect to some accessible analytical solutions. The influence of the predicted values of the centrifugal correction factor on the onset of static and dynamic instabilities of pipes conveying fluid is also discussed.